将嵌套字典转换为CSV表 [英] Convert Nested Dictionary to CSV Table

问题描述

我正在进行数据挖掘在这里是最简单的：

  rows = defaultdict（dict）
 
用户的艺术家，users.iteritems（）中的艺术家：
艺术家的计数，artists.iteritems（）中的计数：
 rows [artist] [user] = count 
  

现在你有了可以直接写入 csv.DictWriter（） ：

 与open（csvfilename，'wb'）as outf：
 writer = csv.DictWriter（outf，[''] + users.keys（））
 writer .writeheader（）
 writer.writerows（dict（row，** {''：key}）for key，rows.iteritems（））
  

需要生成器表达式为 rows 字典中的每个值添加添加的第一列键值对。

演示：

 >>从集合import defaultdict 
>>> import csv 
>>>> users = {...}＃为简洁起见
>>> rows = defaultdict（dict）
>>>>对于用户，artists.iteritems（）中的艺术家：
 ... for artist，count in artists.iteritems（）：
 ... rows [artist] [user] = count 
。 .. 
>>>> import sys 
>>> writer = csv.DictWriter（sys.stdout，[''] + users.keys（））
>>> writer.writeheader（）
，Angelica，Veronica，Sam，Jordyn，Dan，Bill，Chan，Hailey 
>> key.iteriter（string，** {''：key}）for row，rows.iteritems（）中的行
 Strokes，2.5,3.0,5.0,4.0,4.0 ,,, 4.0 
 Blues Traveler，3.5,3.0,5.0，，3.0,2.0,5.0，
 Phoenix，5.0,4.0,5.0,5.0,3.0,2.0,5，
 Broken Bells，2.0，，2.0， 4.5,4.0,3.5,1.0,4.0 
 Deadmau5 ,,,, 4.0,4.5,4.0,1.0,1.0 
 Norah Jones，4.5,5.0,3.0,5.0 ,,, 3.0,4.0 
 Slyly Stoopid，1.5,2.5,4.0,4.5,4.5,3.5,1.0，
 Vampire Weekend，2.0 ,,, 4.0,2.0,3.0，，1.0 
  

I'm going through a data mining tutorial and I'm using the following dictionary.

users = {
    "Angelica": {
        "Blues Traveler": 3.5, 
        "Broken Bells": 2.0, 
        "Norah Jones": 4.5, 
        "Phoenix": 5.0, 
        "Slightly Stoopid": 1.5, 
        "The Strokes": 2.5, 
        "Vampire Weekend": 2.0
    },         
    "Bill":{
        "Blues Traveler": 2.0, 
        "Broken Bells": 3.5, 
        "Deadmau5": 4.0, 
        "Phoenix": 2.0, 
        "Slightly Stoopid": 3.5, 
        "Vampire Weekend": 3.0
    },
    "Chan": {
        "Blues Traveler": 5.0, 
        "Broken Bells": 1.0, 
        "Deadmau5": 1.0, 
        "Norah Jones": 3.0, 
        "Phoenix": 5, 
        "Slightly Stoopid": 1.0
    },
    "Dan": {
        "Blues Traveler": 3.0, 
        "Broken Bells": 4.0, 
        "Deadmau5": 4.5, 
        "Phoenix": 3.0, 
        "Slightly Stoopid": 4.5, 
        "The Strokes": 4.0, 
        "Vampire Weekend": 2.0
    },
    "Hailey": {
        "Broken Bells": 4.0, 
        "Deadmau5": 1.0, 
        "Norah Jones": 4.0, 
        "The Strokes": 4.0, 
        "Vampire Weekend": 1.0
    },
    "Jordyn":  {
        "Broken Bells": 4.5, 
        "Deadmau5": 4.0, 
        "Norah Jones": 5.0, 
        "Phoenix": 5.0, 
        "Slightly Stoopid": 4.5, 
        "The Strokes": 4.0, 
        "Vampire Weekend": 4.0
    },
    "Sam": {
        "Blues Traveler": 5.0, 
        "Broken Bells": 2.0, 
        "Norah Jones": 3.0, 
        "Phoenix": 5.0, 
        "Slightly Stoopid": 4.0, 
        "The Strokes": 5.0
    },
    "Veronica": {
        "Blues Traveler": 3.0, 
        "Norah Jones": 5.0, 
        "Phoenix": 4.0, 
        "Slightly Stoopid": 2.5, 
        "The Strokes": 3.0
    }
}

I want to convert this into a .csv file so that when I open it in Excel, I get a table with the songs on the rows side and the names on the columns side:

Are there any in-built python methods which will help me achieve this?

解决方案

You'll have to transpose from columns containing rows to rows containing columns. Using a collections.defaultdict() object would be easiest here:

rows = defaultdict(dict)

for user, artists in users.iteritems():
    for artist, count in artists.iteritems():
        rows[artist][user] = count

Now you have dictionaries that can be written directly to a csv.DictWriter():

with open(csvfilename, 'wb') as outf:
    writer = csv.DictWriter(outf, [''] + users.keys())
    writer.writeheader()
    writer.writerows(dict(row, **{'': key}) for key, row in rows.iteritems()) 

The generator expression is needed to give each value in the rows dictionary the added first column key-value pair.

Demo:

>>> from collections import defaultdict
>>> import csv
>>> users = { ... }  # elided for brevity
>>> rows = defaultdict(dict)
>>> for user, artists in users.iteritems():
...     for artist, count in artists.iteritems():
...         rows[artist][user] = count
... 
>>> import sys
>>> writer = csv.DictWriter(sys.stdout, [''] + users.keys())
>>> writer.writeheader()
,Angelica,Veronica,Sam,Jordyn,Dan,Bill,Chan,Hailey
>>> writer.writerows(dict(row, **{'': key}) for key, row in rows.iteritems()) 
The Strokes,2.5,3.0,5.0,4.0,4.0,,,4.0
Blues Traveler,3.5,3.0,5.0,,3.0,2.0,5.0,
Phoenix,5.0,4.0,5.0,5.0,3.0,2.0,5,
Broken Bells,2.0,,2.0,4.5,4.0,3.5,1.0,4.0
Deadmau5,,,,4.0,4.5,4.0,1.0,1.0
Norah Jones,4.5,5.0,3.0,5.0,,,3.0,4.0
Slightly Stoopid,1.5,2.5,4.0,4.5,4.5,3.5,1.0,
Vampire Weekend,2.0,,,4.0,2.0,3.0,,1.0

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